1) I tried the methods given in the forum without much luck. I have a Sony Vaio Windows 8 -preinstalled laptop. I downloaded ubuntu and copied it to flash drive and tried to reboot - I get a message the flash drive is empty - when the flash drive clearly has Ubuntu.
2)The other problem is I had earlier tried to install using Windows installer, I got an error message but the screen goes back to a page offering me the choice of the operating system between Ubuntu and Windows 8. When I click Ubuntu I get the error message again re the missing boot file.
I would appreciate some help